CN114110081A

CN114110081A - Helicopter undercarriage buffer

Info

Publication number: CN114110081A
Application number: CN202111381976.4A
Authority: CN
Inventors: 汪兰明; 张松; 焦阳
Original assignee: China Helicopter Research and Development Institute
Current assignee: China Helicopter Research and Development Institute
Priority date: 2021-11-19
Filing date: 2021-11-19
Publication date: 2022-03-01
Anticipated expiration: 2041-11-19
Also published as: CN114110081B

Abstract

The invention discloses a helicopter undercarriage buffer, which comprises a piston rod, an outer barrel and an inner cavity, wherein: one end of the piston rod is movably assembled into one end of the outer cylinder through a sealing structure and is fixedly connected with a throttle valve arranged in the outer cylinder through a fixing sleeve, and a first floating piston is arranged in the piston rod and used for separating a low-pressure air cavity in the piston rod from an oil return cavity; the inner cavity is arranged in the outer cylinder, a high-pressure air cavity is arranged in the inner cavity, one end of the inner cavity penetrates through the throttle valve and is connected with the piston rod, one end of the piston rod is movably assembled outside the inner cavity, and the high-pressure air cavity is separated from an oil return cavity of the piston rod through a second floating piston; a cavity between the outer cylinder and the inner cavity is a hydraulic oil cavity, hydraulic oil is injected into the hydraulic oil cavity through an oil injection nozzle, and the flow of the hydraulic oil is controlled by a throttle valve between the hydraulic oil cavity and an oil return cavity of the piston rod; the end part of the outer cylinder is uniformly distributed with burst diaphragms and is communicated with the high-pressure gas in the inner cavity. The invention can effectively improve the energy absorption efficiency of the buffer and can control the peak load of the buffer.

Description

Helicopter undercarriage buffer

Technical Field

The invention relates to the field of undercarriage design, in particular to a helicopter undercarriage buffer.

Background

Landing gear is a device for aircraft to run and move about on the ground. The landing gear can reduce the stress of the airplane by reducing the impact which is generated by the airplane to different degrees when the airplane lands on the ground and moves on the ground. The key part for buffering and absorbing energy is a buffer. If the design of the buffer is not reasonable, the airplane can bear larger load, and the weight of the airplane is increased. Meanwhile, in the field of helicopters, along with the development of helicopter technology, the requirement on the viability of passengers in danger of the helicopters is gradually improved. Due to the restriction of special rotor structure, low flying height and other factors of the helicopter, passengers are difficult to escape by means of parachuting, ejecting a lifesaving system and the like when dangerous situations occur in the air. The adoption of the crash-resistant technology has important significance for improving the survival rate of the helicopter. At present, a double-cavity oil-gas type buffer is mostly adopted in the anti-landing gear crash design of a helicopter, and the technical development of the buffer is mature.

The traditional double-cavity oil-gas type buffer not only meets the control requirement of normal landing load, but also meets the requirement of full-dynamic characteristic, prevents ground resonance, and simultaneously meets the requirements of crash landing energy absorption, load and stroke control. This makes the high pressure chamber fill the pressure of gas higher, and when large speed landed, the high pressure chamber basically did not work for the energy-absorbing efficiency of undercarriage is low. If the pressure of the high-pressure cavity is reduced, the buffer is soft, and when the helicopter crashes, the landing gear cannot absorb all energy, so that the crash-resistant effect cannot be achieved.

Disclosure of Invention

The invention aims to provide a helicopter undercarriage buffer which is used for meeting the design requirement of a helicopter for resisting the crash of an undercarriage.

In order to realize the task, the invention adopts the following technical scheme:

a helicopter landing gear bumper comprising a piston rod, an outer barrel and an inner cavity, wherein:

one end of the piston rod is movably assembled into one end of the outer cylinder through a sealing structure and is fixedly connected with a throttle valve arranged in the outer cylinder through a fixing sleeve, and a first floating piston is arranged in the piston rod and used for separating a low-pressure air cavity in the piston rod from an oil return cavity;

the inner cavity is arranged in the outer barrel, a high-pressure air cavity is arranged in the inner cavity, one end of the inner cavity penetrates through the throttle valve and is connected with the piston rod, one end of the piston rod is movably assembled outside the inner cavity, and the high-pressure air cavity is separated from an oil return cavity of the piston rod through a second floating piston;

a cavity between the outer cylinder and the inner cavity is a hydraulic oil cavity, hydraulic oil is injected into the hydraulic oil cavity through an oil injection nozzle, and the flow of the hydraulic oil is controlled by a throttle valve between the hydraulic oil cavity and an oil return cavity of the piston rod;

the end part of the outer cylinder is uniformly distributed with burst diaphragms and is communicated with the high-pressure gas in the inner cavity.

Furthermore, the outer cylinder is provided with a stopper, and the stopper is fixed on the outer cylinder by using the inner steel bushing, the outer steel bushing and the shear pin.

Furthermore, the piston rod, the outer cylinder and the inner cavity are of a cylinder structure, and the support sleeve, the throttle valve and the retainer are hollow pieces.

Furthermore, the other end of the piston rod is provided with an inflating nozzle for inflating low-pressure gas into the low-pressure cavity in the piston rod.

Furthermore, one end of the inner cavity is connected with a high-pressure inflating nozzle, and the high-pressure air cavity is filled with high-pressure air through the high-pressure inflating nozzle.

Furthermore, the inner steel bushing, the outer steel bushing and the shearing pin are uniformly distributed in a plurality of groups in the circumferential direction; the inner steel bushing and the outer steel bushing are respectively fixed in a fixing hole in the outer barrel and a fixing hole in a hoop arranged on the surrounding inner cavity, and penetrate through the inner steel bushing and the outer steel bushing through a shearing pin.

Furthermore, when the buffer is compressed by a load, the piston rod moves towards the inner part of the outer cylinder, hydraulic oil in a pressure oil cavity in the outer cylinder flows to an oil return cavity in the piston rod through the throttle valve, and the hydraulic oil generates a damping force through the throttle valve to slow down the compression of the buffer; the hydraulic oil pushes the floating piston to move, and then the gas of the low-pressure gas cavity is compressed; when the gas pressure of the low-pressure gas cavity is increased to the filling pressure of the high-pressure gas cavity, the second floating piston is started, and the low-pressure gas cavity and the high-pressure gas cavity are compressed simultaneously; an equilibrium state is reached when the gas pressure rises to a level that balances the external load to which the damper is subjected.

Further, after the load is relieved, the gas pressure in the piston rod enables the piston rod to extend outwards, and the oil in the oil return cavity is returned to the oil pressing cavity.

Compared with the prior art, the invention has the following technical characteristics:

the helicopter undercarriage buffer provided by the invention can effectively improve the energy absorption efficiency of the buffer and can control the peak load of the buffer.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a sectional view of the installation of the burst disk;

the reference numbers in the figures illustrate: 11 piston rod, 12 outer cylinder, 13 inner cavity, 101 first floating piston, 102 fixed sleeve, 103 throttle valve, 104 low pressure cavity, 105 oil return cavity, 201 second floating piston, 202 outer steel bushing, 203 shear pin, 204 inner steel bushing, 205 stopper, 206 burst disk.

Detailed Description

Referring to the drawings, the invention provides a helicopter landing gear buffer which mainly comprises a piston rod 11, an outer cylinder 12, an inner cavity 13, a first floating piston 101, a second floating piston 201, a fixed sleeve 102, a throttle valve 103, a stopper 205, an outer steel bushing 202, an inner steel bushing 204, a shear pin 203, a burst disk 206 and the like. Wherein:

the piston rod 11, the outer cylinder 12 and the inner cavity 13 are in a cylindrical structure, and the support sleeve 102, the throttle valve 103 and the stopper 205 are hollow pieces, and the structure of the hollow pieces is shown in fig. 1.

One end of the piston rod 11 is movably assembled into one end of the outer cylinder 12 through a sealing structure and is fixedly connected with a throttle valve 103 arranged in the outer cylinder 12 through a fixing sleeve 102, and a first floating piston 101 is arranged in the piston rod 11 and used for separating a low-pressure air cavity 104 in the piston rod 11 from an oil return cavity 105; the other end of the piston rod 11 is provided with an inflation nozzle for inflating low-pressure gas into a low-pressure cavity 104 in the piston rod 11.

The inner cavity 13 is arranged in the outer cylinder 12, one end of the inner cavity is connected with a high-pressure inflating nozzle, a high-pressure air cavity 207 is arranged in the inner cavity 13, and high-pressure air is inflated through the high-pressure inflating nozzle arranged on the outer cylinder 12; one end of the inner cavity 13 is connected with the piston rod 11 through the throttle valve 103, one end of the piston rod 11 is movably assembled outside the inner cavity 13, and the high-pressure air cavity 207 is separated from the oil return cavity 105 of the piston rod 11 through the second floating piston 201.

The cavity between the outer cylinder 12 and the inner cavity 13 is a pressure oil chamber 208, the pressure oil chamber 208 is filled with hydraulic oil through a filling nozzle, and the flow of the hydraulic oil between the pressure oil chamber 208 and the oil return chamber 105 of the piston rod 11 is controlled through a throttle valve 103 so as to provide necessary damping.

The retainer 205 utilizes an inner steel bushing 204, an outer steel bushing 202 and a shear pin 203 to secure the retainer 205 to the outer barrel 12, a partial cross-sectional view of which is shown in figure 2. A plurality of groups of inner steel bushings 204, outer steel bushings 202 and shear pins 203 are uniformly distributed in the circumferential direction; specifically, the inner steel bushing 204 and the outer steel bushing 202 are fixed in a fixing hole of the outer cylinder 12 and a fixing hole of a collar provided around the inner cavity 13, respectively, and penetrate through the inner steel bushing 204 and the outer steel bushing 202 by a shear pin 203.

The burst disk 206 is disposed at the end of the outer barrel 12 and is in communication with the high pressure gas 207 in the inner chamber 13, as shown in the sectional view of fig. 2.

The working process is as follows:

when the buffer is compressed by a load, the piston rod 11 moves towards the inner part of the outer cylinder 12, hydraulic oil in a pressure oil cavity 208 in the outer cylinder 12 flows to an oil return cavity 105 in the piston rod 11 through the throttle valve 103, and the hydraulic oil generates damping force through the throttle valve to slow down the compression of the buffer; the hydraulic oil pushes the floating piston 101 to move, thereby compressing the gas of the low pressure gas chamber 104. As the gas pressure of the low pressure gas chamber 104 increases to the filling pressure of the high pressure gas chamber 207, the second floating piston 201 is actuated, and the low pressure gas chamber 104 and the high pressure gas chamber 207 are compressed at the same time. The system is balanced when the gas pressure rises to a level that balances the external load on the damper. When the load is relieved, the gas pressure in the piston rod 11 causes the piston rod 11 to extend outward, returning the oil pressure in the oil return chamber 105 back into the oil pumping chamber 208.

When landing normally, the high-pressure air chamber 207 of the buffer can participate in energy absorption at the same time, and the energy absorption efficiency is improved. When the piston rod 11 is compressed to the stopper 205 position at the time of crash, the shear pin 203 for fixing the stopper 205 is broken by the piston rod 11, and the shock absorber load can be reduced to below the design value and a longer compression stroke can be generated. As the piston rod 11 continues to compress, the high pressure gas in the high pressure gas chamber 207 will burst through the burst disk 206 provided on the top of the outer barrel 12, and the high pressure gas will be discharged to the atmosphere, in such a way that the load transmitted to the fuselage is limited and the function of the bumper is not affected.

The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equally replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application, and are intended to be included within the scope of the present application.

Claims

1. A helicopter landing gear bumper comprising a piston rod (11), an outer barrel (12) and an inner cavity (13), wherein:

one end of the piston rod (11) is movably assembled in one end of the outer cylinder (12) through a sealing structure and is fixedly connected with a throttle valve (103) arranged in the outer cylinder (12) through a fixing sleeve (102), and a first floating piston (101) is arranged in the piston rod (11) and used for separating a low-pressure air cavity (104) in the piston rod (11) from an oil return cavity (105);

the inner cavity (13) is arranged in the outer cylinder (12), a high-pressure air cavity (207) is arranged inside the inner cavity (13), one end of the inner cavity (13) penetrates through the throttle valve (103) to be connected with the piston rod (11), one end of the piston rod (11) is movably assembled outside the inner cavity (13), and the high-pressure air cavity (207) is separated from an oil return cavity (105) of the piston rod (11) through a second floating piston (201);

a cavity between the outer cylinder (12) and the inner cavity (13) is a hydraulic oil chamber (208), hydraulic oil is injected into the hydraulic oil chamber (208) through an oil injection nozzle, and the flow of the hydraulic oil is controlled between the hydraulic oil chamber and an oil return chamber (105) of the piston rod (11) through a throttle valve (103);

the end part of the outer cylinder (12) is uniformly distributed with burst diaphragms (206) and is communicated with high-pressure gas (207) in the inner cavity (13).

2. A helicopter landing gear bumper according to claim 1, characterized in that the outer barrel (12) is provided with a retainer (205), the retainer (205) being secured to the outer barrel (12) by means of an inner steel bushing (204), an outer steel bushing (202) and a shear pin (203).

3. A helicopter landing gear bumper according to claim 1, characterized in that the piston rod (11), outer cylinder (12), inner cavity (13) are of a cylindrical construction and the support sleeve (102), throttle valve (103) and stop (205) are hollow pieces.

4. A helicopter landing gear bumper according to claim 1, characterized in that the other end of the piston rod (11) is provided with an inflation nozzle for inflating a low pressure chamber (104) within the piston rod (11) with low pressure gas.

5. A helicopter landing gear bumper according to claim 1, wherein one end of the inner cavity (13) is connected to a high pressure inflation nozzle, and the high pressure air cavity (207) is inflated with high pressure air through the high pressure inflation nozzle.

6. A helicopter landing gear bumper according to claim 1, characterized by inner steel bushings (204), outer steel bushings (202) and shear pins (203) evenly distributed in circumferential groups; the inner steel bushing (204) and the outer steel bushing (202) are respectively fixed in a fixing hole in the outer cylinder (12) and a fixing hole in a hoop arranged on the surrounding inner cavity (13), and penetrate through the inner steel bushing (204) and the outer steel bushing (202) through a shearing pin (203).

7. A helicopter landing gear bumper according to claim 1 wherein when the bumper is compressed by a load, the piston rod (11) moves inwardly of the outer barrel (12) and hydraulic oil in a hydraulic oil chamber (208) in the outer barrel (12) flows through the throttle (103) to an oil return chamber (105) in the piston rod (11) where the hydraulic oil generates a damping force through the throttle to slow the compression of the bumper; the hydraulic oil pushes the floating piston (101) to move, and then the gas of the low-pressure gas cavity (104) is compressed; when the gas pressure of the low-pressure gas cavity (104) is increased to the filling pressure of the high-pressure gas cavity (207), the second floating piston (201) is started, and the low-pressure gas cavity (104) and the high-pressure gas cavity (207) are compressed simultaneously; an equilibrium state is reached when the gas pressure rises to a level that balances the external load to which the damper is subjected.

8. A helicopter landing gear bumper according to claim 7, characterized in that when the load is relieved, the gas pressure within the piston rod (11) causes the piston rod (11) to extend outwardly, returning the oil within the oil return chamber (105) to the pressurized oil chamber (208).